6.6-stable review patch. If anyone has any objections, please let me know.
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From: Juergen Gross jgross@suse.com
commit b1c2cb86f4a7861480ad54bb9a58df3cbebf8e92 upstream.
Call the Xen hypervisor via the new xen_hypercall_func static-call instead of the hypercall page.
This is part of XSA-466 / CVE-2024-53241.
Reported-by: Andrew Cooper andrew.cooper3@citrix.com Signed-off-by: Juergen Gross jgross@suse.com Co-developed-by: Peter Zijlstra peterz@infradead.org Co-developed-by: Josh Poimboeuf jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/xen/hypercall.h | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-)
--- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -39,9 +39,11 @@ #include <linux/string.h> #include <linux/types.h> #include <linux/pgtable.h> +#include <linux/instrumentation.h>
#include <trace/events/xen.h>
+#include <asm/alternative.h> #include <asm/page.h> #include <asm/smap.h> #include <asm/nospec-branch.h> @@ -91,9 +93,17 @@ extern struct { char _entry[32]; } hyper void xen_hypercall_func(void); DECLARE_STATIC_CALL(xen_hypercall, xen_hypercall_func);
-#define __HYPERCALL "call hypercall_page+%c[offset]" -#define __HYPERCALL_ENTRY(x) \ - [offset] "i" (__HYPERVISOR_##x * sizeof(hypercall_page[0])) +#ifdef MODULE +#define __ADDRESSABLE_xen_hypercall +#else +#define __ADDRESSABLE_xen_hypercall __ADDRESSABLE_ASM_STR(__SCK__xen_hypercall) +#endif + +#define __HYPERCALL \ + __ADDRESSABLE_xen_hypercall \ + "call __SCT__xen_hypercall" + +#define __HYPERCALL_ENTRY(x) "a" (x)
#ifdef CONFIG_X86_32 #define __HYPERCALL_RETREG "eax" @@ -151,7 +161,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h __HYPERCALL_0ARG(); \ asm volatile (__HYPERCALL \ : __HYPERCALL_0PARAM \ - : __HYPERCALL_ENTRY(name) \ + : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \ : __HYPERCALL_CLOBBER0); \ (type)__res; \ }) @@ -162,7 +172,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h __HYPERCALL_1ARG(a1); \ asm volatile (__HYPERCALL \ : __HYPERCALL_1PARAM \ - : __HYPERCALL_ENTRY(name) \ + : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \ : __HYPERCALL_CLOBBER1); \ (type)__res; \ }) @@ -173,7 +183,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h __HYPERCALL_2ARG(a1, a2); \ asm volatile (__HYPERCALL \ : __HYPERCALL_2PARAM \ - : __HYPERCALL_ENTRY(name) \ + : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \ : __HYPERCALL_CLOBBER2); \ (type)__res; \ }) @@ -184,7 +194,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h __HYPERCALL_3ARG(a1, a2, a3); \ asm volatile (__HYPERCALL \ : __HYPERCALL_3PARAM \ - : __HYPERCALL_ENTRY(name) \ + : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \ : __HYPERCALL_CLOBBER3); \ (type)__res; \ }) @@ -195,7 +205,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h __HYPERCALL_4ARG(a1, a2, a3, a4); \ asm volatile (__HYPERCALL \ : __HYPERCALL_4PARAM \ - : __HYPERCALL_ENTRY(name) \ + : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \ : __HYPERCALL_CLOBBER4); \ (type)__res; \ }) @@ -209,12 +219,9 @@ xen_single_call(unsigned int call, __HYPERCALL_DECLS; __HYPERCALL_5ARG(a1, a2, a3, a4, a5);
- if (call >= PAGE_SIZE / sizeof(hypercall_page[0])) - return -EINVAL; - - asm volatile(CALL_NOSPEC + asm volatile(__HYPERCALL : __HYPERCALL_5PARAM - : [thunk_target] "a" (&hypercall_page[call]) + : __HYPERCALL_ENTRY(call) : __HYPERCALL_CLOBBER5);
return (long)__res;